This is a screen shot of Painter Essentials 5, which I was using to learn Painter in 2015. If you are just starting to digital paint Painter Essentials is a good program to start with. It is meant to be a stepping stone to upgrade later to the full Painter, but it does stand alone for much of digital painting. There are many videos on Youtube to learn from. I think the currant version is 8 in 2021.

YOu can download trial versions of most digital painting programs. Escape motions has one for Rebelle too.

I do advise you to learn the basics of art and using computers before starting any of these. Some can sketch and paint on their own, but those of us who do not can learn by education and practice, practice, practice.